Deadly virus stalks Southern Oregon deer

The deadly adenovirus that has been decimating urban blacktails this summer in Southern Oregon has biologists worried that it might be spreading to migratory herds.

Mark Freemanfor the Tidings

The deadly adenovirus that has been decimating urban blacktails this summer in Southern Oregon has been discovered in forested areas, worrying biologists that it might be spreading to migratory herds.

Dead deer recently have been discovered in the Buck Prairie area off Dead Indian Memorial Road in the hills east of Ashland and high in the East Evans Creek drainage, with other reports coming from the Shale City area.

All are locales frequented highly migratory black-tailed deer herds.

"It makes us a little more nervous than when you hear about a dead deer in east Medford or Ashland or somewhere else where we know it's chronic," says Steve Niemela, an ODFW wildlife biologist in Central Point. "It's pretty widespread."

A similar disease outbreak among migratory deer in the late 1980s was originally attributed to blue tongue, but biologists now believe it was an early showing of the adenovirus before its official diagnosis in Southern Oregon.

Until now, recent adenovirus outbreaks have occurred in these urban areas, where unnaturally high deer densities, lack of predation and active feeding and watering by residents was thought to play a role in its spread.

But now reports are coming in droves, and not just from the traditional deer disease hotbeds of Ashland, Jacksonville and urban-interface areas, Niemela says.

"It's hard to know if you're hearing reports of where the deer are dying or just where the people are," Niemela says.

That's why Niemela is asking archery hunters and others who take to Southern Oregon's backwoods to report any dead deer they discover. This is the third year since 2009 that the disease has popped up among migratory and local deer — so-called “city deer” — and it's perhaps the largest outbreak since 2002, when more than 1,000 blacktails died from adenovirus.

First diagnosed in Northern California in the mid-1990s, adenovirus hemorrhagic disease is spread easily among deer. It can be passed through the breath of infected deer and by the sharing of food and water. That's why it is often associated with urban deer being fed and watered by residents, as well as with drought conditions that can push migratory deer into closer proximity.

Infected deer can suffer from bloody diarrhea and mouth lesions that keep it from feeding.

In some cases, the deer suffer massive internal hemorrhaging. In other cases, field necropsies have revealed a liter or more of liquid in the lungs of infected animals.